The present invention relates to a battery module, a method for its operation, and its use.
In battery modules or battery packs, a plurality of battery cells is usually connected to one another in an electrically conducting manner. Here high-voltage batteries, in particular, sometimes contain safety-critical or function-critical bolted joints. The preload force applied, and in particular the maintenance of the latter over the service life of such a high-voltage battery, is a critical factor for the safe operation of such a high-voltage battery. Conventionally, standardized or also non-standardized safety elements such as, for example, encapsulated adhesives, are used to secure bolted joints. In the case of bolted joints for electrical high-current or high-voltage connections, however, such conventional bolted joint safety elements from the mechanical engineering sector often cannot be used. This applies in the field of battery modules, for example, to the bolted joints of terminals of lithium-ion battery cells, with, for example, appropriate cell connectors or battery module connectors within a battery pack.
In DE 20 2013 010 307 U1, US 2004/0179918 and CN 105115652 devices can be found that can be used to determine the quality of a bolted joint or its change in length, on the basis of an ultrasound measurement method.
This can be used, for example, to determine the preload force or clamping force on a connecting component.